Change In Ocular Alignment Research Articles

Study of postoperative changes in ocular alignment in surgically corrected esotropia

Background Esotropia (ET) represents an ocular alignment disorder characterized by the eyes’ inward deviation. Aim This work aimed to compare changes in postoperative ocular alignment at 6 weeks as well as 6 months following the surgical procedure among cases, who were initially surgically adequately corrected for ET, and to determine if preoperative characteristics are correlated with these changes in ocular alignment. Patients and methods Our prospective clinical trial study involved 30 patients aged between 1 and 40 years, who developed comitant ET and had not undergone any strabismus surgery before. Results A positive weak association (r=0.406) was documented between the age of ET onset and the 6th month postoperative alignment. The age of onset of ET in both groups (infantile and partially accommodative ET) showed a significant difference (P=0.001). The differences in alignment between 1st week and 6th week and between 1st week and 6th month were significant (P<0.001). Mean change in alignment at 6th week postoperatively was significantly different between amblyopic cases and nonamblyopic cases (P=0.012). The age of onset of ET and the degree of preoperative ET less than 50 prism diopters (PD) showed a significant difference between the successful versus unsuccessful cases at the 6th month postoperative (P=0.002 and 0.031, respectively). Conclusion The higher age of ET onset (nearly above 2.5 years) and the lower preoperative angle of deviation (below 40 prism diopter) are associated with a slightly better surgical outcome at the 6th month postoperatively.

Stability of Ocular Alignment After Teprotumumab Therapy in a Cohort of Patients With Thyroid Eye Disease and Baseline Diplopia.

Teprotumumab is a monoclonal antibody that is effective in treating patients with thyroid eye disease (TED) and has been shown to produce subjective improvements in diplopia in this group. The aims of this study were to evaluate the rate and timing of recurrence/worsening of diplopia after teprotumumab treatment in a cohort of patients with TED presenting with diplopia at baseline. A retrospective chart review of 15 patients with diplopia secondary to TED, treated with teprotumumab, was conducted in a single-center academic institution. The primary outcome was the rate of recurrence/worsening of diplopia after completing teprotumumab. Secondary outcomes include the time to recurrence/worsening of diplopia and clinical activity scores (CAS) to correlate with changes in ocular alignment. Fifteen patients met the inclusion criteria for this study, and 7 of these had recurrence of diplopia (46.7%). Two patients had worsening of CAS to ≥4, 6 had worsening of CAS to 3, and the other 7 had CAS ≤2 during the follow-up period. The mean follow-up period was 20.4 months (SD 7.2) after completing teprotumumab. The mean time to diplopia recurrence/worsening was 8.8 months (range 6.7-12.2, SD 1.8). Patients with TED and baseline diplopia have a substantial rate of recurrence/worsening of diplopia after teprotumumab therapy, suggesting that they may not have stable ocular alignment immediately after treatment. Strabismus surgeons may need to weigh the significant risk of disease relapse when planning optimum timing for surgical correction.

Objective Diplopia Outcomes for Patients Treated With Teprotumumab for Thyroid Eye Disease.

Thyroid eye disease (TED) is a condition caused by inflammatory damage to the periocular tissue that often leads to double vision. Teprotumumab is an insulin-like growth factor 1 receptor antibody that was FDA approved for the management of TED in 2020, although much is yet to be elucidated regarding its effects on diplopia outcomes among patients with TED. Diplopia is a significant and life-altering effect of TED. Previous studies have reported the effect of teprotumumab on double vision subjectively using the Gorman diplopia score. However, there is a gap in the literature addressing the effect of teprotumumab treatment on objective ocular alignment measures. The purpose of our study was to address this gap. We performed a retrospective review of patients who were diagnosed with TED, presented with diplopia, and treated with teprotumumab in a single-center academic ophthalmology practice. The primary outcome was change in ocular alignment in primary gaze position at 6 months (completion of teprotumumab treatment). Secondary outcomes included change in ocular alignment in other gaze positions, proptosis, eyelid position, and clinical activity score (CAS) at 6 months compared with baseline. To determine what factors may predict ocular alignment response to teprotumumab, we analyzed baseline characteristics among 3 groups, divided based on whether ocular alignment was worsened, stable, or improved at 6 months. Seventeen patients met inclusion criteria, 3 (18%) worsened, 10 (59%) were stable, and 4 (24%) improved. CAS ( P = 0.02) was significantly different among the groups and was higher in those who worsened and those who improved compared with those who remained stable. Right gaze horizontal prism deviation ( P = 0.01) and left gaze horizontal prism deviation ( P = 0.03) were significantly different among the groups, with a greater degree of left gaze horizontal prism deviation in the worse group than the stable group ( P = 0.04). Our study demonstrated that most patients remained stable after teprotumumab treatment regarding ocular alignment in primary gaze and the number of patients who improved was slightly higher than the number of patients who worsened after teprotumumab treatment. There are some baseline measures, such as CAS and right and left gaze horizontal prism deviation that can help better predict how a patient will respond to teprotumumab treatment. Our results can better inform physicians of how to counsel patients with TED when considering teprotumumab therapy.

Physiological exophoria did not increase the incidence of myopia in rural school children in Taiwan.

This study evaluated the incidence rate and risk factors for developing myopia in elementary school students in Chiayi, Taiwan. This prospective cohort study comprised 1816 students without myopia (grades 1 to 5 in Chiayi County). The students underwent a noncycloplegic ocular alignment examinations using an autorefractometer and completed a questionnaires at baseline and at a 1-year follow-up. A univariate logistic regression was used to assess the effects of the categorical variables on new cases of myopia. A multinomial logistic regression was then conducted. A chi-squared test was used to compare new cases of myopia in terms of ocular alignment. A Cox hazard ratio model was then used to validate factors associated with changes in ocular alignment. A P value of <.05 was considered significant. In 370 participants with new cases of myopia out of 1816 participants, a spherical error of −1.51 ± 0.6 diopters was noted at follow-up. The baseline ocular alignment was not a significant risk factor for developing myopia (exophoria vs orthophoria: OR 1.26, 95% CI 0.97–1.62; other vs. orthophoria: OR 1.15, 95% CI 0.73–1.82). However, new cases of myopia (HR 1.36, 95% CI 1.14–1.61), and baseline ocular alignment (exophoria vs orthophoria: HR 3.76, 95% CI 3.20–4.42; other vs orthophoria: HR 3.02, 95% CI 2.05–4.45) were associated with exophoria at follow-up. This study provided epidemiological data on the incidence of myopia in elementary school students in Chiayi, Taiwan. It also demonstrated that physiological exophoria does not predispose patients to developing myopia.

Bupivacaine injection for comitant horizontal strabismus: clinical and radiological results.

To report the outcomes of bupivacaine injection for the treatment of comitant horizontal strabismus and evaluate clinical effectiveness and associated radiological changes. This prospective observational clinical study was conducted on 10 patients with comitant horizontal strabismus of up to 40 prism diopters. Ophthalmologic examinations and three-dimensional orbital magnetic resonance imaging were performed pre and post-injection (at first, third, and 12th months). A 4.5 ml of 0.5% bupivacaine was injected into the extraocular muscle under topical anesthesia using an electromyography in all patients. The mean follow-up time at post bupivacaine injection and mean deviation at primary position were was 17 ± 2 months and 21.3 prism diopters, respectively. The mean changes in ocular alignment, enlargement of the cross-sectional area in the injected muscle, and volumetric enlargement were 7.7 PD, 12%, and 17% at the first year post-injection, respectively. No severe or persistent complication was observed. Ptosis and mydriasis were noted post-injection due to the anesthetic effects of bupivacaine but disappeared within 2 h post-injection. Bupivacaine injection improved eye alignment in small-angle horizontal comitant strabismus, effectively diagnosed with orbital magnetic resonance imaging to evaluate volumetric changes of the extraocular muscles. Further clinical studies with larger numbers of patients should be performed to define optimal dosages, concentration, and application method and dose-response relationship.

Surgical outcomes following rectus muscle plication versus resection combined with antagonist muscle recession for basic horizontal strabismus

To evaluate change in ocular alignment and surgical success of rectus muscle plication versus resection when coupled with antagonist muscle recession for basic esodeviations and exodeviations. The medical records of consecutive patients with basic horizontal strabismus who underwent a rectus muscle plication or resection combined with a known amount of antagonist muscle recession from January 2009-June 2016 by one surgeon were reviewed retrospectively. Changes in ocular alignment and surgical success at 4-16weeks after surgery and reoperation rates for plication compared to resection were assessed. Success was defined as undercorrection of ≤10Δ and overcorrection of ≤4Δ at distance. A total of 162 patients with basic esotropia (88 lateral rectus muscle plications; 74 lateral rectus resections) and 60 patients with basic exotropia (31 medial rectus muscle plications; 29 medial rectus resections) were included. Success rates at 4-16weeks after surgery were 95.5% for lateral rectus plication, 89.2% for lateral rectus resection, 77.4% for medial rectus plication, and 96.6% for medial rectus resection. No significant differences were found when analyzing the change in ocular alignment between the plication and resection groups for patients with either basic esotropia or basic exotropia. Reoperation rates were low for all groups (range, 3.2%-5.4%) during a follow-up period of 4weeks to 72months. Horizontal rectus muscle plication produced similar changes in ocular alignment and surgical success compared to rectus muscle resection at 4-16weeks after surgery when coupled with comparable amounts of antagonist muscle recession.

Reduced surgical success rate of rectus muscle plication compared to resection

To evaluate the surgical success of rectus muscle plication compared to resection and to compare the short- and long-term changes in ocular alignment after both procedures. The medical records of all patients who underwent a rectus muscle tightening procedure (resection or plication) at a single institution over a 5-year period by a single surgeon were reviewed retrospectively. Binocular alignment was recorded before and immediately after surgery and again at 6-12weeks and final follow-up visit. Primary outcome was surgical success rate, defined as distance alignment of ≤10Δ for horizontal and ≤6Δ for vertical strabismus. Secondary outcomes were reoperation rate and postoperative alignment drift. A total of 72 surgeries were identified for inclusion: 48 resections and 24 plications. Surgical success was significantly higher in the resection group than in the plication group (89% vs 58%; P=0.005) at both 6-12weeks' follow-up (P=0.005) and at mean final follow-up of 19±13months (range, 3-56months [n=48]; P=0.03). Reoperations were performed in 3 patients in the plication group (12.5%), all for undercorrection; there were no reoperations in the resection group (P=0.03). Rectus muscle plication has many potential advantages over resection, including sparing ofthe ciliary circulation. In our experience, however, patients treated with plication hadlowersurgical success rates and a higher reoperation rate. Surgeons should monitor theirlong-term results before considering plication as their procedure of choice over resection.

Esotropia with an accommodative component after surgery for infantile esotropia compared to primary accommodative esotropia

To compare the clinical outcomes of patients with an esotropia with an accommodative component after infantile esotropia surgery and patients with primary refractive accommodative esotropia. The medical records of patients with postoperative (secondary group) and primary refractive accommodative esotropia (primary group) were reviewed retrospectively. Changes in ocular alignment, refractive error, weaning rate, decompensation rate over time, and sensory outcomes were compared. The overall change in ocular deviation with glasses correction was -0.5Δ/year in the secondary group and -0.2Δ/year in the primary group (P=0.010). The overall change in spherical equivalent refractive error was -0.2 D/year in the secondary group and -0.3 D/year in the primary group (P<0.001). The latest stereoacuity result was poorer in the secondary group than in the primary group (P=0.027). No significant differences in the decompensation or weaning rates were detected between groups. The changes in refractive error and the amount of esotropia over time were different between the secondary group and the primary group. Although refractive error was significantly lower and stereoacuity was poorer in the secondary group compared to the primary group, the majority of patients in the secondary group maintained good control of ocular alignment after hyperopic correction.

The Effect of Amblyopia Treatment with Patching on Ocular Alignment

Purpose: To evaluate the effect of patching on ocular alignment in children with unilateral amblyopia. Methods: We evaluated the change in ocular alignment during and after patching in patients who had started amblyopia treatment with patching, and analyzed the aspects of change according to the cause and severity of amblyopia, type and magnitude of deviation, type of refractive error, and age at initiation. A change of eight prism diopters (PD) or more in horizontal deviation, or two PD or more in vertical deviation was considered significant. Results: A total of 209 patients were enrolled; 135 had amblyopia associated with anisometropia, 50 with strabismus, 19 with combined cause, and 5 with deprivation. After patching, there was no change in distant deviation in 177 patients (84.7%), while a decrease was noted in 23 patients (11.0%) and an increase in nine patients (4.3%). The angle of deviation decreased in 7.4% of anisometropic amblyopia, 20.0% of strabismic amblyopia, 10.5% of combined amblyopia, and 20.0% of deprivation amblyopia. The angle of deviation increased in 4.4% of anisometropic amblyopia, 5.3% of combined amblyopia, and 40.0% of deprivation amblyopia. The angle of deviation decreased in 24.2% of exodeviation, and 21.6% of esodeviation, but there was no change in vertical deviation among the studied patients. The angle of deviation decreased in 31.9% of patients with deviation greater than 8 PD. The change did not differ according to severity of amblyopia, type of refractive error, or age. Among the successes, decrease in deviation was more common until they achieved equal visual acuity between both eyes, while the increase during tapering of patching. Conclusions: Change in ocular alignment may occur after patching in some patients with amblyopia, and seems to be more frequent in cases associated with horizontal deviation greater than 8 PD. J Korean Ophthalmol Soc 2016;57(2):302-309

Aniseikonia induced by cataract surgery and its effect on binocular vision.

This study measured aniseikonia before and after the first and second cataract surgeries in ametropic adults. The relationship of aniseikonia to anisometropia and its effect on stereopsis, ocular alignment, and clinical symptoms were determined. Seventeen patients scheduled to have bilateral cataract surgery with 2 diopters or more ametropia participated. Patients were evaluated before cataract surgery and 4 weeks (±1 week) after the first and second surgery. Visual acuity, refractive error, aniseikonia, stereopsis, ocular alignment, and visual symptoms were determined at each visit. Aniseikonia increased after the first cataract surgery. The increase in aniseikonia occurred in concert with increased anisometropia and resulted in poorer stereopsis overall. Aniseikonia and anisometropia 1 month (±1 week) after the second cataract surgery returned to near baseline and were associated with better stereopsis. The amount of aniseikonia showed substantial variance and could not be predicted by the amount of induced anisometropia. Changes in ocular alignment were minimal. Statistically significant changes in patient symptoms between study visits were infrequent. Aniseikonia induced by cataract surgery may not be a substantial problem for ametropic adults with normal binocular vision, at least in the short term.

Impact of laser refractive surgery on ocular alignment in myopic patients.

To evaluate the impact of myopic keratorefractive surgery on ocular alignment. This prospective study included 194 eyes of 97 myopic patients undergoing laser refractive surgery. All patients received a complete ophthalmic examination with particular attention to ocular alignment before and 3 months after surgery. Patients with a mean age of 26.6 years and a mean refractive error of -4.83 diopters (D) myopia were treated. Asymptomatic ocular misalignment was present preoperatively in 46 (47%) patients: a small-angle heterophoria (1-8 prism diopters, PD) in 36%; and a large-angle heterophoria (>8 PD)/heterotropia in 11%. Postoperatively, the change in angles of 10 PD or greater occurred in 3% for distance and 6% for near fixation: in 7% of the patients with orthophoria, in 3% of those with a small-angle heterophoria, and in 18% of those with a large-angle heterophoria/heterotropia. No patient developed diplopia. The preoperative magnitude of myopia or postoperative refractive status was not related to the change in ocular alignment. The higher anisometropia was associated with a decrease in deviation (P=0.041 for distance and P=0.002 for near fixation), whereas the further near point of convergence tended to be related with an increase in near deviation (P=0.055). Myopic refractive surgery may cause a change in ocular alignment, especially in cases with a large-angle heterophoria/heterotropia. There is also a chance of improvement of misalignment in patients with anisometropia.

Changes in the Interpupillary Distance Following General Anesthesia in Children With Intermittent Exotropia: A Predictor of Surgical Outcomes

To determine whether changes in ocular alignment following general anesthesia, as measured by interpupillary distance, can be used as a predictor for surgical outcomes in children with intermittent exotropia. The authors obtained digital photographs of 40 children with exotropia and 20 children with epiblepharon (control group) before and immediately after induction of general anesthesia in the primary supine position. Differences in the anatomic interpupillary distance (aIPD) for each patient were measured and compared with the preoperative angles of deviation. They were also correlated with surgical outcomes on the first day and 1 year after surgery. All 60 patients demonstrated an increase in aIPD following general anesthesia. The mean change in aIPD in patients with exotropia was similar to that in patients with epiblepharon (3.78% ± 2.53% and 3.15% ± 1.05%, respectively). In patients with exotropia, there was a significant positive linear correlation between the preoperative distance deviation (P) and the change in eye position (A): A = 0.362 P - 4.488, r(2) = 0.476 (P < .001). Five (71%) of seven patients whose changes were outside the 80% confidence interval for expected values had poor surgical outcomes on the first postoperative day and four had unsatisfactory results 1 year after surgery. Changes in aIPD following general anesthesia were strongly correlated with preoperative angle of deviation. Therefore, they may be a useful predictor of surgical outcomes in children with exotropia.

Classifying Stability of Misalignment in Children With Esotropia Using Simulations

To determine the sensitivity and specificity of several classification rules for stability and instability of angle in childhood esotropia. We conducted 10 000 Monte Carlo simulations of participants with no actual change in angle of esotropia during follow-up, where "observed" changes in ocular alignment were sampled from a distribution of measurement errors for the prism and alternate cover test. Additional simulations were conducted for a range of "true" changes (1.0, 2.5, 4.2, 5.0, 7.5, and 10.0 prism diopters [PD] per visit) with up to 10 follow-up visits. We then estimated sensitivities and specificities for specific rules for retrospectively classifying stability (all measurements within 0, 5, 10, or 15 PD) and instability (≥2 measurements differing by ≥10 PD, etc) across a fixed number of visits. Results were extended to classifying ocular alignment stability and instability prospectively based on a varying number of measurements. For a series of 4 measurements, the rules that optimized sensitivity and specificity were "all measurements within 5 PD" for stability and "at least 2 measurements differing by 15 PD or more" for instability. For a series of 3 measurements, all 3 measurements needed to be identical to confirm stability. We derived definitions of stability and instability in childhood esotropia using estimates of actual measurement error that may be useful for clinical practice and for future clinical studies of esotropia.

Change in ocular alignment after topical anesthetic cataract surgery

To report the incidence of, and change in ocular misalignment following topical anesthetic cataract surgery. Prospectively, 160 consecutive patients who were scheduled for cataract surgery under topical anesthesia were evaluated. All patients had a complete ophthalmic examination, including ocular alignment evaluation, just before and 1 day, 1 week, 3 weeks, and 2 months after cataract surgery. Preoperatively, 26 patients had ocular misalignment. Mean deviation in these preexisting misalignment was 7.2 +/- 6.8 prism diopters (PD). Postoperatively, the angle of deviation improved to 5.4 +/- 7.4 PD. Acquired ocular misalignment after cataract surgery occurred in 12 of 160 patients (8%) at 1 day, and seven of 131 (5%) at 2 months. None of these seven patients sought medical attention for the diplopia. The overall incidence of topical anesthesia-related change in ocular alignment after uneventful cataract surgery was 5%. However, no patients had symptomatic diplopia. Topical anesthetic cataract surgery could abolish the risk of postoperative diplopia and improve the heterophoric status of preexisting misalignment.

Reduction of Deviation Angle During Occlusion Therapy: In Partially Accommodative Esotropia with Moderate Amblyopia

PurposeTo evaluate changes in ocular alignment in partially accommodative esotropic children age ranged from 3 to 8 years during occlusion therapy for amblyopia.MethodsAngle measurements of twenty-two partially accommodative esotropic patients with moderate amblyopia were evaluated before and at 2 years after occlusion therapy.ResultsMean deviation angle with glasses at the start of occlusion treatment was 19.45±5.97 PD and decreased to 12.14±12.96 PD at 2 years after occlusion therapy (p<0.01). After occlusion therapy, 9 (41%) cases were indications of surgery for residual deviation but if we had planned surgery before occlusion treatment, 18 (82%) of patients would have had surgery. There was a statistical relationship between increase of visual acuity ratio and decrease of deviation angle (r=-0.479, p=0.024).ConclusionsThere was a significant reduction of deviation angle of partially accommodative esotropic patients at 2 years after occlusion therapy. Our results suggest that occlusion therapy has an influence on ocular alignment in partially accommodative esotropic patients with amblyopia.

The Effect of Amblyopia Therapy on Ocular Alignment

We sought to describe the change in ocular alignment at 2 years after treatment of amblyopia in children younger than 7 years of age at enrollment. A randomized clinical trial of patching versus atropine for 6 months followed by standard clinical care for 18 months was conducted in 357 children with anisometropic, strabismic, or combined amblyopia (20/40-20/100) whose ages ranged from 3 to younger than 7 years at enrollment. Ocular alignment was evaluated at enrollment and after 2 years of follow-up. At enrollment when tested at distance fixation, 161 (45%) children were orthotropic, 91 (25%) had a microtropia (1-8 Delta), and 105 (29%) had a heterotropia >8 Delta. Of the 161 patients with no strabismus, similar proportions of patients initially assigned to the patching and atropine groups developed new strabismus by 2 years (18% vs. 16%, P = 0.84). Of these cases of new strabismus, only 2 patients in the patching group and 3 patients in the atropine group developed a deviation that was greater than 8 Delta. Microtropia at enrollment progressed to a deviation greater than 8 Delta with similar frequency in both treatment groups (13% vs. 15%, P = 1.00). Of the 105 patients with strabismus greater than 8 Delta at enrollment, 13% of those in the patching group and 16% of those in the atropine group improved to orthotropia without strabismus surgery. Strabismus surgery was performed in 32 patients during the 2-year study period. Patients who had amblyopia treatment with patching or atropine for 6 months followed by standard clinical care were found to have similar rates of deterioration and improvement of ocular alignment. When parents begin amblyopia treatment for children without strabismus, they should be warned of the possibility of development of strabismus, although it is most often a small angle deviation. Strabismus resolved after amblyopia therapy in some cases.

A new surgical technique for ocular fixation in congenital third nerve palsy

Purpose To present a new technique of ocular fixation to restore and maintain the ocular alignment in primary position for patients with total third nerve paralysis. Method We fixated the globe (medial rectus muscle insertion) to the medial palpebral ligament insertion at the anterior lacrimal crest by using nonabsorbable 5-0 polyester sutures in a prospective study of 5 patients (5 eyes) with congenital total third nerve paralysis. A large recession of the lateral rectus muscle (12 to 16 mm) was also performed in four patients. Results Four patients achieved satisfactory ocular alignment and one patient had residual exotropia. After an initial exotropic shift, no significant change in ocular alignment was observed during the follow-up period of 6 to 9 months. Mild fullness and congestion over the medial rectus muscle area was observed in the immediate postoperative period in all the patients, which resolved in about two months time. Conclusion This technique of ocular fixation is easy, safe, and effective for the management of exotropia secondary to total third nerve paralysis.

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Incidence of ocular misalignment and diplopia after uneventful cataract surgery

Purpose To evaluate the incidence of ocular misalignment and diplopia after uneventful cataract surgery. Setting An outpatient private practice eye institute. Methods One hundred thirty-eight patients referred to 1 cataract surgeon were prospectively evaluated. Orthoptic evaluations were performed within 1 month before and then 1 day, 1 week, and 1 month after cataract surgery. Anesthesia was by retrobulbar injection, and cataract extraction was done by phacoemulsification. Results Cataract surgery was performed in 118 patients. Preoperatively, 16 patients had ocular misalignment; 10 were phoric, 4 were intermittently tropic, and 2 were tropic. Follow-up evaluation was obtained for 101 patients (86%) at 1 day, 91 (77%) at 1 week, and 88 (75%) at 1 month. A change in ocular alignment occurred in 22 of 101 patients (22%) at 1 day, 9 of 91 (10%) at 1 week, and 6 of 88 (7%) at 1 month. Only 1 patient who had a change in alignment at 1 month was symptomatic. Conclusions A persistent change in ocular alignment after uneventful cataract surgery occurred in 7% of patients. However, symptomatic diplopia was uncommon (1 in 118; 0.85%) in this relatively small series.

Changes in ocular alignment and pointing accuracy after sustained passive rotation of one eye

We have investigated the contribution of ocular muscle proprioception (OMP) to the long-term maintenance of ocular alignment in normal human beings. Using a scleral suction lens, one eye was rotated laterally 30 deg away from the position of the other eye. This procedure selectively affects OMP without altering the efferent copy of the ocular motor command. The passively displaced eye was covered white the unimpeded eye fixed upon a stationary target. The suction lens was removed after 6 or 10 min and the measures of alignment begun immediately. Three tests were used to determine the effects of the deviation on ocular alignment: the Lancaster red-green test; saccadic eye movement responses to stepping targets; and hand pointing to monocularly presented targets. All three tests indicated a change of ocular alignment of about 2–4 deg, lasting 5–10 min: sustained temporal deviation resulted in exophoria (relative divergence of the visual axis), and sustained nasal deviation induced esophoria (relative convergence). Binocular viewing rapidly abolished the effect. The hand pointing test showed a large shift in the perceived position of a target during monocular viewing with either eye and its amplitude was correlated with the change of ocular alignment. These results indicate that a sustained passive rotation of one eye can lead to a persistent change in ocular alignment even after the eye is released, without any disparity cues. We further suggest that central mechanisms, based upon ocular motor afferents, rather than passive orbital mechanical factors, are the main cause of this phenomenon.